What is the primary source of energy for prolonged aerobic exercise?

The primary source of energy for prolonged aerobic exercise is derived from fat stores. During extended periods of moderate-intensity exercise, the body shifts its energy reliance from carbohydrates to fat stores as a more sustainable fuel source.

Fat oxidation provides a significant amount of ATP (adenosine triphosphate), which is essential for muscle function during longer-duration activities. The body has large reserves of fat, and it can metabolize these stores efficiently, especially when the intensity of the exercise allows for adequate oxygen supply. This oxidation of fats is particularly advantageous in aerobic situations, where oxygen is available to facilitate the breakdown of fat.

While carbohydrates can provide quick energy during high-intensity workouts, they are limited in terms of storage capacity in the body and are usually tapped into during the initial stages of exercise or in high-intensity bursts. Protein, amino acids, and other sources play a lesser role in aerobic exercise, primarily serving as complementary energy sources when carbohydrates and fats are insufficient. Understanding this shift to fat utilization during prolonged aerobic activities underscores the significance of fat as a vital energy source in endurance sports and activities.